Television apparatus



April 30, 1935.

A. J. CAWLEY TELEVI S ION APPARATUS Filed May 1,4, 1951 ji e 0 Jmankozone-of such media.

Patented Apr. 30, 1935 UNITED PATENT o-FeicE 17 Claims.

The invention relates td-scanning apparatus "for television purposea andisintended to' apply to means for transmitting images, pictures,

writing, and the like, by means oi -wire or wire- "less apparatus; Oneof the objects is the pro,- duction of the mostfinely-grainedimage'bythe use of asingle rotating medium which isprovidedwith a plurality of light modulating'means. *Suchmodulatingmeans has heretofore beencarlied on aplurality of rotating media,---'andthe present invention aims to dispense with all but Such a singlerotating medium may assume many different forms' in' carrying out theinvention in practice,-andit is to be-distinctly understood that thetype of medium described and illustrated is merely one of many formsthat are covered by the appended claims.

This application is a continuationin -part ap- "plication of myapplications -Serial Number "468,117, filed July 15. 1930 1 for'I'elevision aplens -fi is found to be moving tothe right at a stillgreater speed than that of'the-cylinder 'C.

paratus, Serial -Number'-473;660, filed :August 7, 1930; for Scanningapparatus andSerial Number -5 l3,373,- filed February 4, 1981,-forRefiextelevision system.

One of the light modulating media'car'ried on the rotating medium actsto speed uptherate of traversal oi the image, anotherasts tointerruptthe light to-give a chopper effect and a third -brings-about-aslowshifting of the position-of the light beam.

The invention will be more thoroughly understood from the followingdescription of a specific embodiment when read 'in connection with theaccompanying drawing, which Figure 1 is an elevationalside View of theapparatus. 7 g

V Figure 2 isan elevational view in cross-section partly of theapparatus,- the section=-being taken on a line passing through the'slotSpf Figure' 1. *Figure 3 isa side elevational view oftheapparatus, beingthe side opposite'that illustrated in Figure l.

Figure 4 is a plan view o f the apparatus as illustrated in Figure 3. T

Figure 5- is-a side elevational view of a special --modification of thereflecting means forming part of the invention.

In'Fig-ure 1,D is a disk which is mounted upon -a shaft and which isfirmly attached to cylin- Lder C. :The twoelements just mentioned may bereferred to as a single disk-cylinder rotating-elemerit. "-Thisdisk-cylinder-rotates at a definite :speed andis the only-e1ement thatrotates in fine -apparatus. *The diskDis -attached in the middle portionof cylinder C. an image o'f -the object, as desired. 'Cylinder 'C-rotates-tothe right; lenses'2; 4, etc.,' therefore are moved to theright. 'Lens- 2 iorms an image i in the prism 3-- and-also moves thelight to the right at a rate equalto that of the movement Z isthe objector 'ofthecylinder C. This is described in the above applications. TheprismB reflects the light back through the adjacent lens 4, andincidentally of an image in prism 5, as described in the prewhich hasbeen reflected from prism-Band which has had its directionof motionreversed thereby, ina direction oppositeto that of the movement orthelight. Theligha'after it -has traversed Again; animage is formed inprism L-and the lightleaving' this prism is found to have' -ha'd= its Idirection -of motion reversed, so that *it" is *moving-to the-left. Itenters prism 8, which reflects it downward inthe plane of the drawingfrom the observer. This throws the 'light beam upon the diskD at theexact area W-hichis repeatedly traversed by the light -slots 9, *ortheir equivalents, which may belenses, or-o'ther. It =-will be observed'here'that thelight is-moving te -the left at a three-fold augmented rateof that-of the disk Dcarrying' the slots=9. Therefore, the-relativespeed of the light beam an'd the slot 9 is equalto 'thesum of theirspeeds. There is a shifting of the light beam projected through theslotto the right at a -speed equal to the speed of the slot.

There'is a seriesof rapidly moving 'flat light beams moving to theright, the light of which is moving to the left ata much greater speed.The beam is -made up of light that is taken from every portion 'oithe-image, andwhich therefore traverses the 'image at-a very greatspeed. "Theslots produce a chopper eifect whi'ch isso desirablefor-television purposes. From the abovegit willjbe understood that theimage has been scanned in the form of a beam'of 'rectangularcrosssection covering one dimension of theimage. 'It is'now necessarytoexplore the elemental' areas of this rectangle by means of a spiralaperturey-cylind'rical lens, or the like. The light,- after" leaving theslot 9 entersprism A on the opposite side'of -causes the light to movein a direction opposite -10 to that ofthe cylinder C. Lens 4 movesthrough this reflected light and causes-the reformation disk D (seeFigure 2). It is directed upward through the slot S which is in the formof a helix distributed around the periphery of the cylinder C. Thishelical slot S acts to completely explore the elemental portions of therectangular beam, making a complete exploration for one turn of thecylinder.

Figure 2 is a cross-sectional view of disk D and cylinder C. Thisdisk-cylinder is mounted upon shaft E driven by motor M, or itsequivalent. The light is shown coming from prism 5 to lens 6 (not shown)and entering prism 1, from which it is reflected into prism 8. Fromprism 8 it is reflected into slot 9, or rather it is reflected upon thearea traversed by slot 9, and the latter scans the beam in the form of anarrow rectangular laterally moving beam of light. This flat, narrowlight beam is seen entering prism A, which reflects it upward throughthe lens B, which acts to prevent a too great diverging of the lightbeam so that the image may be focused in the plane of the element S.This fiat beam of light is then projected upon the under surface of thecylinder C over the area traversed by the helical slot S, which has oneturn disposed over the surface of the cylinder C. This slot permits asmall approximately square beam of light to pass through to thephotoelectric cell P. Lens B is not absolutely essential in certainmodifications, and may be omitted. In this figure, it will be noted thatthe slot S acts to cause the continual shifting of the light beam whichenters the photoelectric cell, to the right.

It would be quite desirable to rotate the disk in a horizontal position,as shown in Figure 4. It will be noted that the latter figureillustrates conventional scanning, that is, from top to bottom and fromleft to right.

Figure 3 is an elevational view of the right side of Figure 2. Thisfigure is partly in cross section, the section being taken on the brokenline shown in Figure 4. The light is shown coming from the image orobject I and entering lens 2, which projects it into the prism 3. It isreflected back into lens 4, while its motion has been reversed. Lens 4augments its speed of movement and reforms the image in prism 5. Thelatter sends it back with a reversed movement through lens 8, whichgives it a further augmented speed of motion, and forms an image inprism l which reverses its direction and sends it into prism 8 (shown inFigure 2), which reflects the light over the area traversed by slot 9,which breaks it up into laterally moving, flat light beams. It thenpasses into prism A, which reflects it through lens B and slot S intophotocell P. Lens 13 may be omitted, if desired.

A very important modification of the invention is as follows: The prismA as shown in Figure 2, may be omitted, with the result that the lightbeam does not pass upward, but passes horizontally to the right. Thephotoelectric cell with the lens B would then be placed in the path ofthis light beam and be directly actuated by it. In this modification,the lenses L, B, 4, etc., should be helically arranged. The shifting ofthe scanning beam should then be performed by means of the helicallyarranged lenses.

Another modification covers the provision of a spiral or helical slot Shaving more than one turn throughout the cylindrical surface of C.

Figure 4 is a plan view of Figure 3. C is the cylinder carrying thelenses 2, 4, 6 and L, etc., and the helical slot S. This is here shownas a virtual slot, and the integrity of the cylinder C and slot S ismaintained by means of flat, very thin metal braces e, which may be evenan inch in width, while their thickness may be that of a razor blade. Inthis manner, the brace will obstruct very little light, while greatrigidity will be given to the cylinder C. Of course, the cylinder C maybe made of transparent material, and the surface covered with darkpaint, dark paper, fabric, etc., or the cylindrical surface may beprovided with a photographically produced representation of the helicalslot S; or a cylindrical lens may be provided. Or, another modificationcovers the use of a neon or other glow lamp of helical form. This lampmay be activated in sections by cooperation with a com mutator, or thelike. The supporting disk is shown at D. The light from the image isreceived by 2, and passes downward to the prism, and upward through lens4 and to prism 5 (not shown in this figure) and downward again throughlens 6. Finally, prism 8 (shown in dotted lines) reflects this lightthrough the slot 9 into prism A (shown in dotted lines). The flattenedbeam is in dotted lines cooperating with slot S. It will be noted thatthe result is the production of the intersecting point i, which shiftsits position in such manner as to expose the successive elemental areasof the image. The flattened beams (indicated by the dotted lines) moveto the right with great rapidity, while the slot S moves slowly from topto bottom. The area is thus scanned from top to bottom, and from left toright.

An objection to the loss of light caused by its passage through thevarious prisms may be offered. Therefore, instead of prisms being usedfor reflecting the light as described above, it is Possible to use othermodifications, such as that illustrated in Figure 5. a and b are twomirrors of any type desired. They may be very thin plate glass sheets,such as those used for polarizing light, which have been silvered; orthey may be polished sheets of metal, such as monel metal, or other. Aground glass surface, or other screen, is shown at c, and is the same asthat described in my application for Reflex scanning referred to above.This ground glass surface acts to provide a screen upon which the imageis formed by the various lenses 2, etc., as described above. Its use isnot absolutely essential. The dotted lines indicate that the image hasbeen produced at the focal point indicated by the crossing of the dottedlines. The image is thus produced on the ground glass surface. The lightcoming from this image is reflected by the surface b and the resultantvertical portion is found to be moving in a direction opposite to thatof the original light entering the reflecting means. The ground glassscreen c may be omitted and the two mirrors a and b used alone.

Having described my invention, I claim as new and desire to secure byLetters Patent:

1. A scanning process consisting in forming a series of laterally movingimages, changing the direction of travel of the light of said imagesthrough two degree angles and reversing the direction of lateralmovement of said images, reprojecting said images with a lateralmovement similar to the original movement in order to produce anincreased speed of lateral movement of said images and rapidlyinterrupting the light of said images.

2. A scanning process consisting in forming a series of laterally movingimages, changing the direction of travel of the light of said images:noeasev :23

nthroug-h -two:-90.-.-degree.--angles Landr reversing the edirection of.lateral .-movement oi? said images; reppr-ojecting said-imagesmith a1lateral movement similarito the-originalemovement in ordertoproduce.-.an-.-increased speed of lateral movement :of :said; images,ragain reversing sthe a'dllGCtiOD -of travelandiof:lateral-movement of:said imagesrand .passing the light, ot said-images through a; series0f31ig-ht. interrupting. areas: having .a .directionwf rmovement'opposite tOSaidY light;

- A scanning.processrconsistmg .-informing a eseries oflaterallyww-movingi images,=;changing the ndirection 1.01? travel :ofthelight: 20ft said; images through two; 90- degreeaangleszandrreversing;the -;=direction eof lateral -movement f said :images, reprojecting saidimages with-.arlaterahmove- .dment similar' to. the .original movement.of: said rtimages. in order. to produce-ran increased-speed of lateral.-.movement' 1 of: said: images; rapidly; interrupting the light:-of:=said.:images,;zand passing said .-;li g=htthrqugh a rectangularlight. varying. area of changing-position.

, 4. -A.-scanning.:apparatus consisting of a single :.moving.=medium,-three :groups of light modulating areas carried. on.said medium, :aplurality. of stationary light reflecting elements, one of said groups:of light modulating areas cooperating with said light reflecting meansto produce an increased rate of movement of a series of images, thesecond of said groups cooperating with said stationary elementsconstituting a chopping means for interrupting the light of saidimages'repeatedly and the third of said groups cooperating with saidstationary elements to produce a beam of light of equal dimensionshaving a speed greater than said moving medium.

5. A scanning apparatus consisting of a single moving medium composed ofa disk and cylinder, a plurality of helically arranged lenses on saidcylinder and a chopping means consisting of a plurality of slots on saiddisk, and stationary reflecting means in cooperative relation with saidlenses and slots for passing light which has traversed said lensesconsecutively through said slots.

6. A scanning apparatus consisting of a single moving medium composed ofa disk and cylinder, a plurality of lenses arranged on said cylinder, ahelical rectangular light limiting area also on said cylinder, achopping means consisting of a plurality of slots on said disk,,and aplurality of light reflecting means stationarily arranged about saidmoving medium acting to consecutively reflect the light through saidlenses in order to produce an increased lateral movement of imagesformed by said lenses and to reflect said light through said slots toproduce a chopper effect and through said helical area to produce asuitably limited and shifting light beam.

7. A single moving medium, a group of image forming elements carried onsaid medium producing a series of laterally moving images, a choppingmeans consisting of a group of light interrupting elements carried onsaid medium, a stationary group of reflecting elements acting to passthe light of said images consecutively through said image formingelements to increase the speed of movement of said images over that ofthe moving medium, and a stationary group of elements acting to pass thelight of said images through said interrupting elements to produce arapidly moving scanning light beam.

8. Means for interrupting a beam of light in a' television apparatusconsisting of a movable medium, a series of light permeable areas borneon said medium, said light permeable areas forming and moving aseries oflight beams-in adefinite'direction, i as series; of chopper areas also;borne on andwmoved by said :medium, stationary; means for reversing. thedirection of motion of *said light =beams andustationarymeans fordiverting Said. .Jightbeams through said series .of;chopper areas awhilesaid: .light beams are; moving, oppositely to said chopper areas. in;order to :produce a I very rapidiinterruption of; said light beams.

-9.-; 'A1;scanning apparatus consisting, of a .mov-

able .gmedium, a series of: image forming elements :borne one-and moved;by said medium to .form 2 thereby -a series of'rnoving light beams; aseries vof. chopper elements. borne onand-movedby said movable gmedium;stationary meansv includingiginclined reflecting surfaces for.accelerating the speed ofcmotion; of said light beams; and reversiingatheddirection ctr-motion thereof relativeto said movable mediumandmeans including an in- -clinedzreflectingsurface. for divertingsaidzaccelerated..::and reversed movement light :zbeams through/saidchopperareas toproduce avery :rapid interruption. of said. light beams.

.; 10. .A scanning, apparatus consisting of .a'movable: medium, a"series oilight permeableareas zbor-nepon said'medium, said. .areas'transmitting and moving .a series. of :light beams in .aldefinitedirection; aseries. of. chopper. areasalso borne on and movedby saidmedium, stationary-means for reversing the direction of motion of andfor reflecting said light beams through said series of chopper areas,said reflected light beams and said chopper areas moving in oppositerelative directions in order to produce a great interruption of saidlight beams and a stationary photoelectric element in cooperativerelation with said interrupted light beams to convert said light beamsinto corresponding electric current.

11. A scanning apparatus consisting of a single rotatable element, aplurality of series of light permeable areas carried on and moved bysaid rotatable element, one of said series consisting of image formingelements arranged in image exploring relation which act to move a seriesof images, means for increasing the speed of and reversing the directionof motion of said images in cooperative relation with the light of saidimages and directing said light through a second of said series, thesecond of said light permeable areas consisting of chopping means incooperative relation with the light of said images, said chopping meansmoving in a direction opposite to that of saidimages in order that thelight constituting said images may be rapidly interrupted and aphotoelectric element upon which the successive elemental areas of saidimages are impinged to produce an image modulated electric current.

12. A scanning apparatus consisting of a single rotatable element, aplurality of series of light permeable areas carried on and moved bysaid rotatable element, one of said series consisting of image formingelements arranged in image exploring relation which act to form and movea series of images, means for increasing the speed of and reversing thedirection of motion of said images in cooperative relation with thelight of said images and directing said light through a second of saidseries, said second series consisting of chopping means in cooperativerelation with the light of said images, said chopping means moving in adirection opposite to that of said images in order that the lightconstituting said images may be rapidly interrupted, means for focussingand moving said images upon a third of said series of light permeableareas, said third series consisting of a longitudinal laterally movinglight permeable area and a photoelectric element receiving the lightfrom said images to pmduce an image modulated electric current.

13. A scanning apparatus consisting of a single rotatable cylinder, arotatable disk fixedly attached to said cylinder at its mid portion, afirst series of light permeable areas borne on one lat eral half of saidcylinder, a second series of light permeable areas borne on said disk,stationary reflecting means for causing light which has traversed saidfirst series to traverse said second series, a third series of lightpermeable areasborne on the other lateral half of said cylinder,stationary means for reflecting light which has traversed said secondseries through said third series and a stationary photoelectric elementin cooperative relation with said light after it has traversed saidthird series.

14. A scanning element consisting of a rotatable cylinder, two series oflight permeable areas arranged on difierent lateral portions of thesurface of said cylinder, each of said series being composed of a typeof light permeable area difierent from that of the other series, arotatable disk fixedly attached to said cylinder along a line situatedbetween said series of light permeable areas and a third series ofdiiferent type of light permeable areas carried on said disk.

15. A scanning apparatus consisting of a rotatable cylinder, two seriesof light permeable areas arranged on different lateral portions of thesurface of said cylinder, each of said series being composed of a typeof light permeable areas different from the other series, a rotatabledisk fixedly attached to said cylinder along a line situated betweensaid series of light permeable areas, a third series of still differentlight permeable areas carried on said disk and a pinrality of stationarymeans including an inclined reflecting surface for consecutivelyreflecting light beams successively through each of said series of lightpermeable areas to obtain a beam that is modified as to form andmovement for scanning purposes.

16. A scanning apparatus in accordance with claim 5 in which aphotoelectric cell is disposed so as to be influenced by the light whichhas traversed said chopping means.

1'7. A scanning apparatus in accordance with claim 13 in which saidstationary reflecting means consists of two reflecting surfaces disposedone on each side of said disk and inclined towards the surface of saiddisk and said cylinder.

ALOYSIUS J. CAWLEY.

